Accurate measurement of altitude (altimetry) is an important technology challenge for small unmanned aerial vehicles (UAVs). Accurate altimetry can be especially important for UAV operation in low altitude environments (e.g., to avoid collisions. Typical current solutions use global positioning satellite (GPS) positioning, which has poor accuracy in height and/or barometric sensors, which are crude in terms of both accuracy and precision. Many current and future applications for UAVs will involve operating near buildings, ships, and trees in all potential light and weather conditions, where global navigation satellite signals are unavailable, leading to the need for alternative altimetry solutions.
Features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.